A very common misconception I often encounter with SQL users is the idea that DISTINCT is something like a function, and that it can take parenthesised arguments. Just recently, I've seen this Stack Overflow question where the OP was looking for a way to express this in jOOQ: SELECT DISTINCT (emp.id), emp.fname, emp.name FROM employee … Continue reading SQL DISTINCT is not a function
Tag: DISTINCT ON
Using DISTINCT ON in Non-PostgreSQL Databases
A nice little gem in PostgreSQL's SQL syntax is the DISTINCT ON clause, which is as powerful as it is esoteric. In a previous post, we've blogged about some caveats to think of when DISTINCT and ORDER BY are used together. The bigger picture can be seen in our article about the logical order of … Continue reading Using DISTINCT ON in Non-PostgreSQL Databases
How SQL DISTINCT and ORDER BY are Related
One of the things that confuse SQL users all the time is how DISTINCT and ORDER BY are related in a SQL query. The Basics Running some queries against the Sakila database, most people quickly understand: SELECT DISTINCT length FROM film This returns results in an arbitrary order, because the database can (and might apply … Continue reading How SQL DISTINCT and ORDER BY are Related